Method of making gratings having interlocked bars



E. w. UTZLER 2,420,112

METHOD OF MAKING GRATINGS HAVING INTERLOCKED BARS May 6, 1947.

Filed Nov. 1, 1941 2 Sheets-Sheet l May 6, 1947. E. w. UTZLER METHOD OFMAKING GRATINGS HAVING INTERLOCKED BARS Filed Nov. 1 1941 J u lv/ a v Vm 0/ 9 m M/ I a A I M 9. d f u Z t u T. u

. 9 q f m u n L M 2 INVENTOR Patented May 6, 1947 UNITED STATES PATENTOFFICE METHOD OF MAKING GRATINGS HAVING INTERLOCKED BARS 1 Claim. 1

This invention pertains to steel grating of the type known as pressedsteel grating, in which the component parts are assembled under pressureand retained in assembled relation through deflection of the crossmembers during the application of the aforesaid pressure.

One object of the present invention is to provide a grating of thecharacter described in which the cross bars are deflected during theassembling of the grating and resist separation from the girder bars ofthe grating by reason of said deflection and frictional engagement ofsaid girder bars and deflected portions of the cross bars.

Another object of the invention is to provide a grating of the characterdescribed, in which the cross bars are only partially dependent uponfrictional engagement with the girder bars to resist separationtherefrom.

Another object of the invention is to provide a grating of the characterdescribed, in which the cross bars space the girder bars independentlyof the engagement between the cross bars and girder bars for the purposeof retaining the said bars in assembled relation.

A further object of the invention is to provide a bearing engagementbetween the intersecting assembled girder and cross bars which is abovethe frictionally engaging portions to prevent destruction of thefrictional engagement between said intersecting portions of the girderand cross bars during the alternate application and release of loadingstresses on said bar or bars.

Steel gratings used as floors of bridges, decks of vessels, platforms ofbuildings and other structures, as coverings for apertures in variousstructures and a variety of other uses are well-known in the art.Various means have been used to retain the component parts of thegrating in assembled relation, such as friction, rivets, welding and acombination of some or all of these means. Each said means hasadvantages as Well as disadvantages. Both welding and riveting areobjectionable as being the most expensive means. The use of friction asthe holding means has been objectionable because loading impacts andvibrations set up in the gratings during their intended use diminish thedegree of frictional engagement between the component parts until it isinsufiicient to retain the grating members in rigid assembled relation.

The majority of gratings utilizing friction to lock the componentmembers thereof in assembled relation are formed by punching slots orotherwise forming apertures in the load-carrying members and forcing thecross bars down into these slots or apertures under considerablepressure. Many of these gratings, during the intended use thereof, havethe cross members pounded into the slots of the load-carrying memberswhich causes Wear of the members at their points of engagement anddestroys the holding power of the frictional engagement between theadjacent portions of these intersecting members. Others of the so-calledfriction-locked gratings distort the cross members during or afterapplication of the assembling pressure thereon as an additional lockingmeans. Here again the cross members being subjected to pounding orvibration are worn or torn at their points of engagement with theload-carrying members, thereby destroying the effectiveness of theholding power of the frictional engagement between the members at thedistorted portions. This latter type of grating is also objectionable inthat the portions of the members being distorted are of such smallcrosssection that they are readily torn or worn at their points ofengagement with the heavier loadcarrying members or they cut into theloadcarrying members.

Most of th well-known methods of assembling grating utilizing frictionalengagement of the girder bars and cross bars to retain the bars inassembled relation perforate or slot one or both intersecting bars insuch a manner that the bearing engagement between the intersecting barsis wholly or in major part below the portions of the bars frictionallyengaged. It will be obvious that in metal gratings the bars have somedegree of elasticity of compressibility under load and when this load isreleased the bars will return to their normal shape. This alternateapplication and release of the load upon the grating will cause relativemovement between adjacent engaging portions of the intersecting barswhich, if continued, breaks the frictional lock between them and causesa wearing away of one or the other of said adjacent engaging surfaces.

In the grating hereinafter described I have utilized the method ofslotting the load-carrying members, hereinafter called girder bars, andpressing the cross members, hereinafter called cross bars, into theslots in the girder bars in order to reduce the cost of manufacture. Ihave eliminated the tendency for tearing, cutting or wearing of themembers at their points of contact in the said slots during the intendeduse of the grating by providing broad bearing surfaces at theintersection of the cross bars and girder bars. I have also eliminatedall tendency to destroy the frictional engagement between theintersecting surfaces of the girder and cross bars by placing thebearing surfaces of the intersecting bars above the frictional engagingportions of the intersecting bars. In addition thereto I have so formedeach cross bar that it has two oppositely deflected or distortedportions engaging each intersecting cross bar at the place ofintersection therewith, thereby materially increasing the holding powerof the deflected and frictionally engaged portions.

In the drawings forming part of these specifications, Fig. 1 shows a lanview of a portion of a grating embodying the invention; Fig. 2 shows asection taken on lines 2-2 of Fig. 1; Fig. 3 shows a section taken onlines 33 of Fig. 1; Fig. 4 shows a cross section of the cross bar beforeassembly with the girder bars; Fig. 5 shows a cross section through thecross bar when assembled with the girder bars; Fig. 6 shows a sideelevation of a portion of a cross bar of the form shown in Fig. 4; Fig.7 is a composite view of a side elevation of a girder bar and threesteps in the assembly of the cross bars therewith; Fig. 8 shows one viewof a locking means for securing the grating in position during theintended use thereof; Figs. 9 and 10 show side elevations at oppositesides of the locking means of Fig. 8.

In the drawings forming part of the specifications wherein likereference characters are used to refer to like parts; the girder barsindicated by reference character I are the load-carrying members and thecross bars '2 serve principally to lock the girder bars in assembledrelation, to brace the girder bars against forces applied in a directiontransversely thereof and to transmit all imposed loads on the cross barsto the girder bars.

Each girder bar I is illustrated as of substantially rectangularcross-section and disposed upon one edge. Obviously the girder bar maybe of any other shape suitable for performing the intended function of'agirder bar. These girder barsare of a suitable'size, depending upon theload to be supported and the spacing of the supports therefor. Spacedlongitudinally of each girder bar I are inverted V-shaped slots 3extending inwardly ofthe bar from the top edge thereof and of a suitablesize and shape to receive the cross bars and deflect same when pressedinto the slots 3. As illustrated in Figs. 3 and 7 of the drawings theslots 3 are of substantially inverted V-shape and of a verticaldimension less than the vertical dimension of the assembled cross bars2. At the apex of the inverted V-shaped slots 3, each side slot isenlarged a'suitable amount to permit ready 'entrance of the undefiectedcross bars as will hereinafter be described. The bottoms of the slots3in the bars I preferably'terminate above the neutral axis of the barsto avoid weakening of the bars to the extent which would occur were theslots carried down below the neutral axis. The inner' top surfaces 4 ofthe intersecting sides of the slots 3 are suitably formed to provide abearing for the cross bars I. These slots 3 in a plurality of girderbars are in transverse align ment. I

'Each cross bar2, when in unassembled position, is of substantiallyinverted U-shape as shown in Figs. 4 and 7 of the drawings and wheninassembled relation with the adjacent girder bars I isof substantiallyinverted V-shape. Spaced longitudinally of each cross bar 2 andcorresponding to the spacing of the girder bars tare a plurality ofslots 5 extending inwardly from the free edge of each armof the crossbar and 'of sufiicient width to permit the ready entrance of the girderbars. Each arm of thecross bar 2 is preferably of less thickness thanthat of thegirder bars and are joined together by an arcuate portioncorresponding in size to the surface at the juncture of the slots 3 inthegirder bars I. Each cross bar 2 is of a length sufficient to span aplurality of girder bars I and prefer- 4 ably extends the width of theparticular section of grating being formed.

As previously referred to, each cross bar is initially formed ofinverted U-shape and is in this form when initially inserted in theinverted v-shaped slots of the girder bar. When each cross bar is firstdisposed across a plurality of spaced girder bars, the slots 5 in thecross bars 2 engage the girder bars I and permit the lower portions ofthe cross bar to move downwardly and between the girder bars. Thisdownward movement of the cross bar is arrested by the portions above theslots therein engaging with the slots 3 in the girder bars I. Pressureis then applied to the so-positioned cross bars and of a sufficientamount to force the portions of the cross bars above the slots 5 thereindown into the slots 3 of the girder bars. During this downward movementof the cross bar, the inverted V-shaped girder bar slots 3 spread and atthe same time distort the cross bars at and between the girder bars intoa form corresponding to that of the slots 3 in the girder bars I. Thismovement continues until the upper inner portions at the juncture of thearms of the cross bars seat on the portions 4 of the girder bars.

When the cross bar 2 has seated on the girder bars 2, as describedabove, the portions of the arms of the cross bar 2 within the slots 3 ofth girder bar may engage the bottom of said latter slots, but need notdo so. In fact, if the cross bar portion within the slots are soproportioned as to terminate above the bottoms of the girder bar slots,assembly of the cross and girder bars is greatly facilitated and a fullbearing of the juncture of the arms of the cross bars upon the portion 4of the girder bars between the slots therein is assured. Inasmuch asthese cross bars are deflected at or above the portion 4 of the girderbar, when entering the slots 3 of the latter the reverse movement musttake place when an attempt is made to remove the cross bar from withinthe slots of the girder bars. Hence each cross bar is doubly locked ineach girder bar and as the bottom of each cross bar is wider than thetop of the slot in the girder bar the cross bar can not be removed-orseparated from the girder bars without a redistortion of the entirecross bar, which i resisted by the girder bar portions between slots 3.

Since the cross bars 2 have bearings on the girder bars I at the points4, which bearings are above theportions of the cross bar engaged in theslots of the girder bar, there is substantially nomovement of the crossbar within the girder bar slots t when vertical load isapplied to thecross bars, so that any frictional engagement between the cross 'andgirder bars'is not destroyed through movement of those portions of thecross bars withintheslots 3 of the girder bars.

There are numerous occasions where it is'desirable to rigidly securesections of grating'in place by the use of fastening means which arequickly and readily moved from locked tounlocked position so that thegrating s'ectionsmay be quickly and readily removed from position orreplaced. One such means is illustrated 'in Figs. 8 to 10 of thedrawings. This locking means utilizes a novel and positive connectionbetween the'grating'sections and the supports therefore to readily andquicklysecure or remove a section of grating to or from the supports.1Referring now to Figs. 8 to 10 of the drawings, reference characters Iand 2 respectively in'diate the assembled girder and cross bars of aportion of a section of grating. Disposed beneath the section of gratingare suitable supporting members l which may be of any desired form andsize arranged in sufficient numbers to provide adequate support for thegrating and the loads imposed thereon. These supports 1 have beenillustrated as inverted pressed channels. One or more of the members 1beneath each section of gratings are used to lock the grating section inplace, in addition to providing a support therefor. One or more of thehereinafter described locking means may be used in looking the gratingsection to a member 1.

Each locking means comprises the members 8 and 9 on opposite sides ofthe member 1 and connected together beneath the member 1 by means of themember 19.

The upper end of member 8 has a jointed connection to a member it whichterminates in a hook-shaped portion l2 inserted in the aperture i8 ofgirder bar 4 beneath the cross bar 2 and between the depending armsthereof. The lower end of member 8 terminates in a jointed connectionwith one end of the member 10.

The members 9 are preferably arranged in pairs on the opposite side ofmember 1. The members 9 are preferably joined together at their upperends and have a jointed connection to a member 14 which terminates in ahook portion 55 inserted in the aperture 16 in girder bar I beneathcross bar 2 and between the depending arms thereof. The lower ends ofeach member 9 terminates in an apertured portion ll depending below thelower edge of member 1. Disposed between these portions ll of members 9is a locking member i8 and connected with said members 9 by means of pinl9 inserted thru the apertured portions i1 and a suitable aperture inmember I8. This pin 19 has a head 29 at one end thereof and an aperturein the opposite end thru which a cotter pin 2! or other suitablefastening means is inserted to retain the pin [9 in position.

Connecting the members 8 and 9 on opposite sides of the member I is amember if! disposed beneath member I. This member ID is preferably afiat substantially rectangular member, one end of which is hinged tomember 8 and the opposite end of which is bifurcated at 22 so that whenthe member 19 is disposed against member 1 the members 9 will lie withinthe bifurcation 22 of member 10. This bifurcated portion of member inalso provides a bearing for the looking member 18 as will now beexplained.

The locking member [8 is preferably a relatively long thin member havinga handle shaped. portion l8 at one end and a, cam shaped head portion I8at the opposite end. This head portion 18* is apertured and mounted onpin [9. The member l9 when mounted on pin I9 is disposed in a directiontransversely of the assembled member 19 and the cam shaped head l8 is soformed that the portion I8 thereof will pass beneath member ID to permitassembly and disassembly of the lockin means. The portion I8 of member18 has a cam shaped surface extending from portion 18 to l8 thereof soas to produce a progressively increasing bearing upon member I as themember I8 is rotated.

The operation of the locking means is as follows. The member 19 ispermanently assembled on member 8 and the end I0 of member 8 isassembled in aperture l3 of girder bar I beneath cross bar 2 The members9 are permanently assembled with member 5 which is engaged in aperture16 of girder bar i beneath cross bar 2 These members 8 and. 9 arepreferably permanently attached to girder bar I on opposite sides of themember 1. The members 9 and assembled locking member 13 are movedlaterally away from member I and member 19 is moved across member I sothat its bifurcated portion projects beyond the side of member 1 asshown in Fig. 8.

The member 9 with member l8 depending therefrom are moved within thebifurcation 22 of member ID and member I8 is disposed beneath member l0.Member i8 is then rotated until portion [8 thereof engages the underside of member I9 and upon a further slight rotation looks the gratingto member 1. The portion I8 is of sufiicient size to take up slightvariations in the members 1, i9 and 9 so that a tight bearing of girderbars 1 on top of member 1 and of member [0 upon the underside of member1 is always obtained.

In the foregoing description and drawings the details of construction ofthe locking means are more or less conventional in form and manyvariations in details of construction will suggest themselves to thoseskilled in the art which may be used without departing from theprinciple of operation of my invention. Likewise variations in thedetails of construction and form of the cross and girder bars willsuggest themselves to those skilled in the art and it is to beunderstood that I do not wish to limit myself to the exact form of theinvention illustrated except as made necessary by the scope of theappended claim.

Having thus described the invention what I claim as new and desire tosecure by Letters Patent is:

The method of making a grating which comprises providing girder bars inspaced relation, each girder bar having spaced inverted substantiallyV-shaped slots extending inwardly from one longitudinal edge thereof sothat the intersection of the slots provide a cross bar bearing portionbelow the plane of said longitudinal edge of the girder bar, providingcross bars of inverted substantially U-shape, and assembling the gratingby forcing the free ends of the cross bar arms into the girder bar slotsand locking the cross bars therein thru progressive deformation untilthe rounded portion of the cross bar engages the bearing providedtherefore on the girder bar.

ELMER W. UTZLER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,612,236 Thomson Dec. 28, 19261,734,660 Williams et a1 Nov. 5, 1929 2,014,451 Pfeifer, Jr Sept. 1'7,1935 2,162,497 Barrett June 13, 1939 455,717 Howard et al. July '7, 18911,301,981 Smith Apr. 29, 1919 1,348,360 Howell Aug. 3, 1920 1,789,280Armstrong Jan. 13, 1931 940,083 Stimpson Nov. 16, 1909 886,515 Jude May5, 1908 1,016,584 Shepherd et a1 Feb. 6, 1912 1,631,691 Nagin June 7,1927 FOREIGN PATENTS Number Country Date 2,029 British 1910

